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React Js MCQs MCQs: 536 Questions & Answers in Programming

536 React Js MCQs MCQs in Programming with answers & explanations. Page 21. Practice objective questions for competitive exams, interviews & self-assessment… Use the answer toggle below to show or hide all solutions, tap an option to check one question, or open a question for its own page.

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React Js MCQs MCQs: 536 Questions & Answers in Programming

What is the purpose of `shouldComponentUpdate`?

How do you ensure a component only mounts once with a side-effect?

Which statement is true about React keys?

Which hook is used to memoize a function in React?

What does `useMemo` do in React?

What does `useRef` return?

How do you pass props to a component in React?

Which React method is used to update the UI when state changes in class components?

What does `React.StrictMode` do?

What is a controlled component?

What is the purpose of `useMemo`?

Which is true about props in React?

What is the return type of a functional component?

How does React achieve better performance?

What happens if you try to render an array in JSX?

What does `defaultValue` do in input elements?

What does JSX stand for in React?

Which of the following is not a valid React hook?

Which method can be used to handle errors in React class components?

Which hook is used to manage complex state logic in React?

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